"There is concern about the possible, serious problem. In the waters off the southern coast, CBS news correspondent Anne Marie green explains. Scientists are predicting a near record massive Gulf of Mexico dead zone where the water holes too little oxygen to sustain marine life. The National Oceanic and Atmospheric Administration says the dead zone off the coast of Louisiana and Texas will be about. Seventy eight hundred square miles. That's the size of Massachusetts. Scientists say one big factor is that the nutrients carried into the Gulf by an unusual amount of runoff from this year. Storms has led to an increase in algae, that uses up a lot of"